Liposuction is a surgical procedure for altering the human form, specifically by removal of localized deposits of fat tissues that are unresponsive to diet or exercise. The procedure is also known as suction lipectomy, lipolysis, and more recently as body contour surgery or body sculpting surgery. It is most often performed by plastic surgeons, although dermatologists, gynecologists, and other surgical specialties also perform the procedure.
The procedure is typically accomplished by inserting a small cannula through an incision in the skin, applying a suction source to the end of the cannula that remains outside of the body, and forcing the working end of the cannula forward and backward in the layer of fatty tissue. The fatty tissue is torn, crushed, or avulsed, and is then aspirated through small openings along the sides of the cannula near the tip and then through a central lumen in the cannula to a tissue canister placed in-line with the cannula and the suction source. The procedure may involve multiple incisions and many passes of the cannula in each incision to achieve the desired cosmetic effect for the patient.
A liposuction cannula is typically a small metal tube with a blunt, closed end at the tip. The blunt, closed end at the tip is intended to minimize damage to tissues as the device is thrust forward. Small openings along the sides of the cannula near the tip create passages between the tissue and the central lumen of the cannula, which is in fluid communication with a suction source, so that tissue and fluids can be aspirated. The suction causes the adipose tissue to be pulled into the openings along the sides of the cannula, and the blunt dissection provided by the surgeon's manipulation of the cannula tears the tissue. The fragments and released fluids are then aspirated through the openings along the sides of the cannula and then through the central lumen of the cannula. Thus, these types of cannulae are designed to accomplish two surgical objectives with a single device. First, they crush, tear, or avulse the fatty tissues such that the tissue fragments and fluids can pass through the openings in the sides of the cannula. Second, the suction source and the central lumen of the cannulae are used to aspirate the tissue fragments and fluids from the operative site.
The liposuction procedure is referred to as a `closed` procedure because the operative site about the tip of the cannula is not directly visualized during the procedure due to the small incision size and the length of the liposuction cannula, which results in the tip area being buried inside the tissue. When a cannula is placed into the fatty tissue through the small incision, a seal is created between the outer surface of the cannula about and along its length and the fatty tissue, preventing the flow of any ambient pressure fluid, such as air, to the operative site about the tip of the cannula. When suction is applied, there exists low pressure inside the cannula at the operative site, the blunt tip area and the side openings, that pulls the tissue into the side openings which is then torn with the motion of the cannula. Because the seal prevents the flow of any ambient pressure fluid to the operative site about the tip or the cannula, the pressure about the tip of the cannula quickly drops to the pressure of the suction source, which is significantly below the ambient pressure. The combination of the above-mentioned seal and the fact that the pressure at the operative site about the tip of the cannula has dropped to the pressure of the suction source greatly reduces, if not completely eliminates, the surgeon's ability to remove tissue fragments and fluids from the operative site because the pressure differential between the operative site at the tip of the cannula and the suction source has been eliminated. Thus, fragments and fluids move not at all or very slowly through the cannula and suction tubing, or clog the tubing. The tip of the cannula must be withdrawn from the patient to such an extent that the seal is broken and the tip and side openings are exposed to ambient air pressure to clear the cannula and suction line. This phenomenon appears to the surgeon as a `clogged` instrument or tubing set.
The liposuction procedure can be traumatic to the patient. The mechanical disruption of the tissues may result in, among other things, bleeding, bruising, temporary numbness, or swelling. The procedure can also be physically demanding on the surgeon because of the forces required to repeatedly push the cannula through the tissue. Further, the final cosmetic result is a function of the skill of the surgeon, the patient, and the type of surgical instrumentation used in the surgery.
Many patents disclose improvements and solutions for liposuction cannulae. U.S. Pat. No. 4,596,553 to Lee discloses a suction cannula with a guide bar attached to the cannula that is used to control the depth of the cannula in the tissue relative to the skin. U.S. Pat. No. 4,735,605 to Schwartz discloses a suction cannula with an outer tube with a longitudinal slot, and an inner tube with a spiral slot which is movable relative to the outer tube. U.S. Pat. No. 5,112,302 to Cucin has a suction cannula with a reciprocating means so that the cannula can be caused to reciprocate relative to the handle. U.S. Pat. Nos. 5,348,535 and 5,643,198, also to Cucin, have a suction cannula with a hollow outer cannula and a hollow inner cannula connected to a reciprocating means. The hollow inner cannula reciprocates within the hollow outer cannula so that tissue pulled into openings in the hollow outer cannula is sheared between the two cannulae. U.S. Pat. No. 5,181,907 to Becker has a tubular member with a plurality of longitudinally extending members projecting radially outward beyond the surface of the tubular member. U.S. Pat. No. 5,665,101 also to Becker has a method of cutting tissue with a rotary powered surgical instrument with an inner and an outer tube, both with cutting windows on the sides of the tubes. U.S. Pat. No. 5,569,178 to Henley has a source of rotary power, an outer tubing, and an inner tubing with flanges. U.S. Pat. No. 5,013,300 to Williams has a single lumen cannula, a handle, a control means for varying the suction forces, and a means to swivel the handle relative to the cannula. This patent includes a means to vent the tubing set from the handpiece back to the suction source, but does nothing to solve the same problem for the cannula. Consequently, the seal and clog problems persist.
While some of the patented devices have claimed improvements and solutions to liposuction cannulae for the problems of tissue trauma, surgeon fatigue, and cosmetic results, none address or appreciate the above-mentioned seal and clog problems and all of the prior devices incorporate tissue fragmentation and tissue aspiration capability in but one cannula. All of these devices are subject to clogging.
There is a need to improve the design of the prior patents to further reduce trauma to the tissues of the patient, resulting in reduced healing times, less bruising, less bleeding, and reduced pain. Accordingly, it is the object of the instrument disclosed herein to produce an improved surgical instrument for the removal of fragmented tissues and fluids from a patient in a closed procedure with minimal damage to remaining tissues and to further increase the speed and thoroughness of the procedure by eliminating the above-mentioned seal and clog problems inherent in this closed procedure and therefore eliminating the clogging of previous designs.